Cathepsin L is involved in cathepsin D processing and regulation of apoptosis in A549 human lung epithelial cells

2004 ◽  
Vol 385 (7) ◽  
Author(s):  
A. Wille ◽  
A. Gerber ◽  
A. Heimburg ◽  
A. Reisenauer ◽  
C. Peters ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cathepsin D ◽  
Human Lung ◽  
Cathepsin L ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Single Chain ◽  
Lung Epithelial ◽  
Induced Apoptosis ◽  
Human Lung Epithelial Cells

AbstractCathepsins are implicated in a multitude of physiological and pathophysiological processes. The aim of the present study was to investigate the function of cathepsin L (catL) in the proteolytic network of human lung epithelial cells and its role in the regulation of apoptosis. We found that catL-deficient A549 cells as well as lung tissue extracts of catL[-/-] mice express increased amounts of single-chain cathepsin D (catD). Degradation experiments indicate that catL specifically degrades the singlechain isoform of catD. Furthermore, we found that catLdeficient cells showed increased sensitivity to apoptosis. Finally, we demonstrate that the inhibition of catD activity by pepstatin A decreased the number of apoptotic cells in catLdeficient A549 cells after anti-Fas treatment. In conclusion, catL is involved in catD processing and the accumulation of catD isoforms in catL-deficient cells is associated with increased rates of spontaneous and anti-Fas-induced apoptosis.

A model to identify novel targets involved in oxidative stress-induced apoptosis in human lung epithelial cells by RNA interference

2010 ◽  
Vol 24 (1) ◽  
pp. 310-318 ◽  
Author(s):  
William E. Wixted ◽  
Chris Kitson ◽  
Jayne C. Colebrook ◽  
Emma J. Roberts ◽  
Steven M. Fox ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Rna Interference ◽  
Epithelial Cells ◽  
Human Lung ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Novel Targets ◽  
Induced Apoptosis ◽  
Human Lung Epithelial Cells

Ionizing radiation enhances matrix metalloproteinase-2 production in human lung epithelial cells

2001 ◽  
Vol 280 (1) ◽  
pp. L30-L38 ◽  
Author(s):  
Jun Araya ◽  
Muneharu Maruyama ◽  
Kazuhiko Sassa ◽  
Tadashi Fujita ◽  
Ryuji Hayashi ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Ionizing Radiation ◽  
Basement Membrane ◽  
Lung Injury ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Radiation Induced ◽  
Human Lung Epithelial Cells

Radiation pneumonitis is a major complication of radiation therapy. However, the detailed cellular mechanisms have not been clearly defined. Based on the recognition that basement membrane disruption occurs in acute lung injury and that matrix metalloproteinase (MMP)-2 can degrade type IV collagen, one of the major components of the basement membrane, we hypothesized that ionizing radiation would modulate MMP-2 production in human lung epithelial cells. To evaluate this, the modulation of MMP-2 with irradiation was investigated in normal human bronchial epithelial cells as well as in A549 cells. We measured the activity of MMP-2 in the conditioned medium with zymography and the MMP-2 mRNA level with RT-PCR. Both of these cells constitutively expressed 72-kDa gelatinolytic activity, corresponding to MMP-2, and exposure to radiation increased this activity. Consistent with the data of zymography, ionizing radiation increased the level of MMP-2 mRNA. This radiation-induced increase in MMP-2 expression was mediated via p53 because the p53 antisense oligonucleotide abolished the increase in MMP-2 activity as well as the accumulation of p53 after irradiation in A549 cells. These results indicate that MMP-2 expression by human lung epithelial cells is involved in radiation-induced lung injury.

scholarly journals Role of Nucleolin in Human Parainfluenza Virus Type 3 Infection of Human Lung Epithelial Cells

2004 ◽  
Vol 78 (15) ◽  
pp. 8146-8158 ◽  
Author(s):  
Santanu Bose ◽  
Mausumi Basu ◽  
Amiya K. Banerjee
Keyword(s):  
Epithelial Cells ◽  
Cell Surface ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Parainfluenza Virus ◽  
Lung Epithelial ◽  
Human Parainfluenza Virus ◽  
Type 3 ◽  
Human Lung Epithelial Cells

ABSTRACT Human parainfluenza virus type 3 (HPIV-3) is an airborne pathogen that infects human lung epithelial cells from the apical (luminal) plasma membrane domain. In the present study, we have identified cell surface-expressed nucleolin as a cellular cofactor required for the efficient cellular entry of HPIV-3 into human lung epithelial A549 cells. Nucleolin was enriched on the apical cell surface domain of A549 cells, and HPIV-3 interacted with nucleolin during entry. The importance of nucleolin during HPIV-3 replication was borne out by the observation that HPIV-3 replication was significantly inhibited following (i) pretreatment of cells with antinucleolin antibodies and (ii) preincubation of HPIV-3 with purified nucleolin prior to its addition to the cells. Moreover, HPIV-3 cellular internalization and attachment assays performed in the presence of antinucleolin antibodies and purified nucleolin revealed the requirement of nucleolin during HPIV-3 internalization but not during attachment. Thus, these results suggest that nucleolin expressed on the surfaces of human lung epithelial A549 cells plays an important role during HPIV-3 cellular entry.

scholarly journals Critical Role of HAX-1 in Promoting Avian Influenza Virus Replication in Lung Epithelial Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Xue Li ◽  
Bingqian Qu ◽  
Ganlin He ◽  
Carol J. Cardona ◽  
Yongchun Song ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Epithelial Cells ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Human Lung ◽  
Early Stage ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Induced Apoptosis ◽  
Human Lung Epithelial Cells

The PB1-F2 protein of influenza A virus has been considered a virulence factor, but its function in inducing apoptosis may be of disadvantage to viral replication. Host mechanisms to regulate PB1-F2-induced apoptosis remain unknown. We generated a PB1-F2-deficient avian influenza virus (AIV) H9N2 and found that the mutant virus replicated less efficiently in human lung epithelial cells. The PB1-F2-deficient virus produced less apoptotic cells, indicating that PB1-F2 of the H9N2 virus promotes apoptosis, occurring at the early stage of infection, in the lung epithelial cells. To understand how host cells regulate PB1-F2-induced apoptosis, we explored to identify cellular proteins interacting with PB1-F2 and found that HCLS1-associated protein X-1 (HAX-1), located mainly in the mitochondria as an apoptotic inhibitor, interacted with PB1-F2. Increased procaspase-9 activations, induced by PB1-F2, could be suppressed by HAX-1. In HAX-1 knockdown A549 cells, the replication of AIV H9N2 was suppressed in parallel to the activation of caspase-3 activation, which increased at the early stage of infection. We hypothesize that HAX-1 promotes AIV replication by interacting with PB1-F2, resulting in the suppression of apoptosis, prolonged cell survival, and enhancement of viral replication. Our data suggest that HAX-1 may be a promoting factor for AIV H9N2 replication through desensitizing PB1-F2 from its apoptotic induction in human lung epithelial cells.

Induction of proinflammatory cytokines in human lung epithelial cells during Rhodococcus equi infection

2013 ◽  
Vol 62 (8) ◽  
pp. 1144-1152 ◽  
Author(s):  
Sara Remuzgo-Martínez ◽  
Lilian Pilares-Ortega ◽  
Lorena Álvarez-Rodríguez ◽  
Maitane Aranzamendi-Zaldunbide ◽  
Daniel Padilla ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Lung ◽  
A549 Cells ◽  
Rhodococcus Equi ◽  
Airway Epithelial Cells ◽  
Lung Epithelial Cells ◽  
Initial Contact ◽  
Structural Level ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Rhodococcus equi is an opportunistic human pathogen associated with immunosuppressed people. While the interaction of R. equi with macrophages has been comprehensively studied, little is known about its interactions with non-phagocytic cells. Here, we characterized the entry process of this bacterium into human lung epithelial cells. The invasion is inhibited by nocodazole and wortmannin, suggesting that the phosphatidylinositol 3-kinase pathway and microtubule cytoskeleton are important for invasion. Pre-incubation of R. equi with a rabbit anti-R. equi polyclonal antiserum resulted in a dramatic reduction in invasion. Also, the invasion process as studied by immunofluorescence and scanning electron microscopy indicates that R. equi make initial contact with the microvilli of the A549 cells, and at the structural level, the entry process was observed to occur via a zipper-like mechanism. Infected lung epithelial cells upregulate the expression of cytokines IL-8 and IL-6 upon infection. The production of these pro-inflammatory cytokines was significantly enhanced in culture supernatants from cells infected with non-mucoid plasmid-less strains when compared with cells infected with mucoid strains. These results demonstrate that human airway epithelial cells produce pro-inflammatory mediators against R. equi isolates.

scholarly journals Proteinase-Activated Receptor-1 Mediates Elastase-Induced Apoptosis of Human Lung Epithelial Cells

2005 ◽  
Vol 33 (3) ◽  
pp. 231-247 ◽  
Author(s):  
Tomoko Suzuki ◽  
Theo J. Moraes ◽  
Eric Vachon ◽  
Hedy H. Ginzberg ◽  
Tsun-Tsao Huang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Lung ◽  
Lung Epithelial Cells ◽  
Lung Epithelial ◽  
Induced Apoptosis ◽  
Human Lung Epithelial Cells

scholarly journals Polymyxins induced metabolic perturbations in human lung epithelial cells

2021 ◽  
Author(s):  
Maizbha U. Ahmed ◽  
Mohammad A. K. Azad ◽  
Mengyao Li ◽  
Darren J. Creek ◽  
Meiling Han ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Untreated Control ◽  
Human Lung ◽  
A549 Cells ◽  
Polymyxin B ◽  
Membrane Lipid ◽  
Lung Epithelial Cells ◽  
Reduced Form ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Inhaled polymyxins are associated with toxicity in human lung epithelial cells involving multiple apoptotic pathways. However, the mechanism of polymyxin-induced pulmonary toxicity remains unclear. This study aimed to investigate polymyxin-induced metabolomic perturbations in human lung epithelial A549 cells. A549 cells were treated with 0.5 or 1.0 mM of polymyxin B or colistin for 1, 4, and 24 h. Cellular metabolites were analyzed using LC-MS/MS and significantly perturbed metabolites (log 2 fold change [FC]≥1, FDR≤0.2) and key pathways were identified relative to untreated control samples. At 1 and 4 h very few significant changes in metabolites were observed relative to the untreated control cells. At 24 h, taurine (log 2 FC = -1.34±0.64) and hypotaurine (log 2 FC = -1.20±0.27) were significantly decreased by 1.0 mM polymyxin B. The reduced form of glutathione (GSH) was significantly depleted by 1.0 mM of polymyxin B at 24 h (log 2 FC = -1.80±0.42). Conversely, oxidized glutathione (GSSG) was significantly increased by 1.0 mM of both polymyxin B (log 2 FC = 1.38±0.13 at 4 h and 2.09 ± 0.20 at 24 h) and colistin (log 2 FC = 1.33±0.24 at 24 h). L-carnitine was significantly decreased by 1.0 mM of both polymyxins at 24 h, as were several key metabolites involved in biosynthesis and degradation of choline and ethanolamine (log 2 FC≤-1); several phosphatidylserines were also increased (log 2 FC≥1). Polymyxins perturbed key metabolic pathways maintaining cellular redox balance, mitochondrial β-oxidation, and membrane lipid biogenesis. These mechanistic findings may assist in developing new pharmacokinetic/pharmacodynamic strategies to attenuate the pulmonary toxicities of inhaled polymyxins and the discovery of new-generation polymyxins.

Microarray analysis of Streptococcus pneumoniae gene expression changes to human lung epithelial cells

2008 ◽  
Vol 54 (3) ◽  
pp. 189-200 ◽  
Author(s):  
Xin-Ming Song ◽  
Wayne Connor ◽  
Shakiba Jalal ◽  
Karsten Hokamp ◽  
Andrew A. Potter
Keyword(s):  
Gene Expression ◽  
Streptococcus Pneumoniae ◽  
Epithelial Cells ◽  
Human Lung ◽  
Cell Envelope ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Pcr Analysis ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Streptococcus pneumoniae infection starts from the respiratory tract where interaction with host epithelial cells occurs. To gain more insights on pneumococcal pathogenesis, an oligonucleotide (oligo)-based microarray was used to investigate gene expression changes of one serotype 3 encapsulated pathogenic S. pneumoniae strain 82 and one unencapsulated avirulent S. pneumoniae strain R6 upon exposure to human lung epithelial cells (A549) for 1 and 3 h, respectively. We observed that genes associated with many functional categories were differentially regulated in strain 82, such as genes in pathogenesis, cell envelope, transcription, translation, transport, metabolism, and unknown functions. In contrast, few genes were changed in strain R6 except for genes in ribonucleotide biosynthesis and unknown functions. Quantitative real-time PCR analysis confirmed the microarray results for most of the genes tested. To further characterize functions of the selected genes, knockout mutants were constructed in strain R6. We demonstrated that 2 genetic loci, SP_2170 (AdcB, zinc ABC transporter) and SP_0157 (hypothetical protein), were involved in adherence to A549 cells. These data suggest that divergent gene expression changes occur in S. pneumoniae pathogenic and avirulent strains during interaction with human lung epithelial cells. Some of those genes are involved in pneumococcal pathogenesis.

Nitric oxide activates chloride currents in human lung epithelial cells

1997 ◽  
Vol 272 (6) ◽  
pp. L1098-L1104 ◽  
Author(s):  
B. Kamosinska ◽  
M. W. Radomski ◽  
M. Duszyk ◽  
A. Radomski ◽  
S. F. Man
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cells ◽  
Human Lung ◽  
A549 Cells ◽  
Lung Epithelial Cells ◽  
Disulfonic Acid ◽  
Patch Clamp Technique ◽  
No Donors ◽  
Lung Epithelial ◽  
Human Lung Epithelial Cells

Epithelial Cl- channels are regulated by various physiological factors, including guanosine 3',5'-cyclic monophosphate (cGMP). Because cGMP mediates many of the physiological actions of nitric oxide (NO), we have studied both the presence of endogenous NO and the effects of exogenous NO on Cl- currents in A549 human lung epithelial cells. We have detected Ca(2+)-dependent NO synthase activity in A549 cells. Using the perforated patch-clamp technique, we have shown that inhibition of this enzyme by NG-monomethyl-L-arginine decreased Cl- current, an effect that was reversed by the NO donor S-nitrosoglutathione (GSNO). In addition, the NO donors GSNO and S-nitroso-N-acetyl-D,L-penicillamine increased whole-cell Cl- currents in A549 cells. This stimulatory effect of the NO donors was sensitive to inhibition by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, suggesting that channels other than the cystic fibrosis transmembrane conductance regulator (CFTR) are involved in the action of NO on A549 cells. In addition, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a selective inhibitor of soluble guanylyl cyclase, decreased NO-mediated stimulation of Cl- currents. Our results suggest that, in lung epithelial cells, NO regulates a non-CFTR Cl- conductance acting via a cGMP-dependent mechanism.

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